Exciting times are afoot. We have just released a Community Technology Preview of DotNetOpenAuth with built in support for OAuth2.
Download it here
Andrew posted a notice to our discussion group earlier today
For those of you chomping at the bit to start development with DotNetOpenAuth upcoming OAuth 2.0 support, now you can.
Please do take notice of the rider that comes with this (and any) CTP;
The public API has not been locked down, and please assume that critical security holes exist, at this early stage in development. The OAuth 2.0 spec is still a moving target, and I have not yet audited all the code to lock it down security-wise. This is a preview so you can begin development with the library and provide early feedback.
Do not "go live" with this version!
And please don't be shy with the feedback. :)
OAuth2 Specification (http://wiki.oauth.net/OAuth-2)